Non-cellular life is life that exists without a cellular structure. This term presumes the phylogenetic scientific classification of viruses as lifeforms, which is a controversial issue.
Hypothesized artificial life, self-replicating machines, and most simple molecules capable of self-replication, such as crystals, are not usually considered living. (See definition of life.)
Some biologists refer to wholly syncytial organisms as "acellular" because their bodies contain multiple nuclei which are not separated by cell membranes, however these cell-bound organisms are outside the scope of the present article.
Read more about Non-cellular Life: History, Virus, Viroid, Controversy, See Also
Famous quotes containing the word life:
“The symbol of perpetual youth, the grass-blade, like a long green ribbon, streams from the sod into the summer, checked indeed by the frost, but anon pushing on again, lifting its spear of last year’s hay with the fresh life below. It grows as steadily as the rill oozes out of the ground.... So our human life but dies down to its root, and still puts forth its green blade to eternity.”
—Henry David Thoreau (1817–1862)